Acyl ureide preparation



Patented Nov. 13, 1951 ACYL UREIDE PREPARATION Eddy W. Eckey,Cincinnati, Ohio, and Andrew Doyle Abbott, Fairfax, Calif., assignors toThe Procter & Gamblecompany, Cincinnati, Ohio, a corporation of Ohio NoDrawing. Application January 2, 1947, Serial No. 719,942

12, Claims. 1

This invention relates to the preparation of fatty acid amides of urea,generically referred to herein as "acyl ureides.

The acyl ureides are useful in many arts, for example as synthetic resinintermediates; waterproofing agents for wood and textiles; accelerators,softeners and anti-oxidants for rubber; dispersing, flotation andwetting agents for use alone or in combination with other such agents;dye intermediates; and parasiticides.

It is an object of our invention to provide a new and improved processfor the preparation of acyl ureides.

It has been suggested to prepare acyl ureides by reacting fatty acidesters of monohydric alcohols (e. g. ethyl stearate), urea, and largequantities of sodium ethylate (a metal alkoxide, also called sodiumethoxide) in the presence of pyridine as an acyl ureide solvent.According to our experience with such a process, however, sodiumethylate reacts with the fatty ester to form soap which promotes theformation of a stable emulsion from which the dissolved ureide can beseparated only with diiiiculty.

We have discovered certain improvements in the production of acylureides involving new practices which in part are directly contrary tothe recommended procedure of the prior art. In brief, our processinvolves reacting a suitable fatty ester (as more fully explained below)and urea under conditions which permit precipitation of the acyl ureideas formed. The interchange of radicals during reaction is therebydirected toward desired acyl ureide formation.

Important features of our process are as follows.

First, in our process the fatty acid ester and urea are reacted in thesubstantial absence of a material having substantial solvent action forthe acyl ureide. vThe use of fluidizing agents to further the reaction,however, such as substantially inert solvents for the ester orsubstantially inert mutual solvents for the ester and urea, which arenot solvents for the acyl ureide is not excluded from the scope of theinvention.

Second, instead of employing monohydric alcohol esters of the fatty acidas suggested in the prior art, we employ polyhydric alcohol esters.Polyhydric alcohol esters used in accordance with our invention appearto have less solvent action for the acyl ureide than the correspondingmonohydric alcohol esters and their use thereby favors the desiredprecipitation of the acyl ureides and the direction of the reactiontoward their f rm tion.

Third, the metal alkoxide (e, g. sodium ethoxide) is used only incatalytic amounts as a molecular rearrangement catalyst for the reactionbetween the fatty acid ester and the urea thereby avoiding the formationof large'quantities of soap and the attending emulsificationcomplications.

Thus the present process comprises contacting a polyhydric alcohol esterof the fatty acid with urea in the substantial absence of a materialhaving appreciable solvent action for fatty acid ureide but in thepresence of catalytic amounts of a suitable molecular rearrangementcatalyst at a temperature below the decomposition temperature of urea(that is, below about 150 C.) and within the range of which the lowerlimit is the lowest temperature at which ester is liquid and the upperlimit is the highest temperature at which fatty acid ureide cancrystallize from the reaction mix as it is formed, and maintaining thetemperature within said range while progressive crystallization of theacyl ureide takes place. A related process of organic radicalinterchange involving the interesterification of triglycerides in whichsolid triglycerides precipitate as formed in the reaction is the subjectof patent application Ser. No. 562,062 (Patent No. 2,442,531) filedNovember 6, 1944, by E. W. Eckey, one of the inventors of thepresentprocess.

The invention will be more fully understood from the following examplesin which the parts are by weight. It is to be understood, however, thatthe examples are merely illustrative of the manner of practicing theinvention and are not to be taken as limiting the scope of the appendedclaims.

Example 1.200 parts of refined and dried coconut oil, parts of urea,parts of dry tertiary butanol, and 2 parts of sodium methoxide (added asa 10% suspension in Xylene) were thoroughly mixed and slowly agitated atabout 50 C. for about '72 hours. Aoyl ureides formed" in the reactionprecipitated. After the reaction period, the mixture, which was alkalineto phenolphthalein, was then acidified and dispersed in Skellysolve H (amixture of commercial hexanes and heptanes in which the ureides aresubstantially insoluble). This mixture was then treated with water towash out unreacted urea, tertiary butanol, catalyst residue, and anymonoglyceride formed in the reaction. Thereafter the Skellysolve H wasdistilled off under reduced pressure. The residue containing the acylureide and fatty glycerides was then treated with petroleum ether toextract unreacted diand triglycerides present.

gently agitated for about 20 hours at about 50.

C. The reaction mix was thereafter acidified with glacial acetic acid toinactivate'the catalyst, then washed on a filter with warm ether toremove ether-soluble triglycerides, then washed with hot water to removetertiary butanol, unreacted urea, monoglyoeride, and other undesiredmaterials soluble or readily dispersible in water.

A 79% yield of an acyl ureide product containing 10.27% nitrogen wasrecovered.

In the above examples we have shown the use of tertiary butanol as amedium in which to conduct the reaction. This material is not a solventother mutual solvents or agents which render the 1 mix fluid but whichare substantially inert and which do not have substantial solvent actionfor the acyl ureide, such as ethyl ether, dioxane, benzene, gasoline,and other hydrocarbons such as hexane, heptane, octane and commercialmixtures thereof may be used.

When fiuidizing agents are used in the practice of the invention theproportion employed is not critical. ing from about one third to abouttwice the combined weight of the ester and urea has been found suitable,but larger or smaller amounts may of course be employed if desirablewithout departing from the spirit of the invention.

The invention is not to be considered as limited to the use of fattyacid triglycerides, or to glycerin esters in general, as the reactantfurnishing the acyl radical. Completely or partially esterifiedpolyhydric alcohols besides glycerol, especially those having not morethan four carbons such as glycol, diethylene glycol, propylene glycoland the like may be employed.

Example 3.90 parts of the diester of cottonseed fatty acids and ethyleneglycol were mixed with 9 parts of finely ground urea. To this mix turewas added 1 part finely divided sodium methoxide. The mixture was heatedto 120 F. and vigorously agitated at this temperature for 50 hours. Atthe end of the run the sodium methoxide was inactivated by the additionof an equivalent amount of glacial acetic acid, unreacted glycol esterwas removed by repeated wash- An amount of this material vary- I ofdiethylene glycol and of propylene glycol may be substituted for theglycol ester actually employed.

Example 3 also demonstrates that the reaction of the process takes placein the absence of substantialquantities of a fluidizing agent as used inExamples 1 and 2.

Although the invention finds its greatest use in the preparation of acylureides of the higher molecular weight fatty acids, that is, fatty acidshaving from about 8 to about 22 carbon atoms I such as caprylic, capric,lauric, myristic, palmitic, stearic, oleic, linoleic, etc., the ureidesof .-lower fatty acids such as acetic, propionic, bu-

tyric, and valeric may be prepared similarly by reaction of a suitableester thereof with urea in a corresponding manner. Of especial interest,however, are the acyl ureides prepared from mixtures of higher fattyacids such as occur in the ing with Skellysolve F, and the crude ureideretained 8.8% nitrogen as compared with 8.90%

theoretical.

Example 3 demonstrates that the reaction of the present invention takesplace when a polyhydric alcohol ester other than a glycerin ester isused. More specifically corresponding ester natural fats and fatty oilsincluding coconut, palm kernel, babassu, cottonseed, soybean, sunflowerseed, sesame, corn, rapeseed, olive, peanut, palm, tallow, herring,sardine, manhaden and others as well as their hydrogenated and partiallyhydrogenated derivatives.

The products formed in the practice of the present invention areprimarily the monoacyl ureides, although some diacyl ureides may bepresent in small proportion. The monoacyl derivatives constitute thedesired product, but it is not necessary to react equivalent amounts ofcombined fatty acid with the urea in order to effect their formation inpredominant proportion. Apparently the diacyl ureides are not'readilyformed under the conditions of this invention and more than oneequivalent of the combined fatty acid may be employed. We have found itdesirable to use in the neighborhood of two equivalents of combinedfatty acid per one equivalent of urea.

The above referred to application of Eckey Ser. No. 562,062 discussesfully the subject of catalysts which are suitable in reactions involvingthe interchange of organic radicals at relatively low temperature. Wehave found that the same class of materials may be employed in thepractice of the present invention, but the constitution of the truecatalytic material is not accurately known. Whatever may be the truecatalyst, it can be shown that substances which are effective inbringing about the interchange of radicals include compounds whichinclude sodium or potassium, for example, combined with any materialless acidic than phenol. Thus various alkoxides such as sodium,potassium, and lithium methoxides, ethoxides, propoxides, and butoxidesare suitable as are the corresponding alkoxides made from alcoholiccompounds in general such as lauryl alcohol, ethylene glycol, oleic acidmonoglyceride, and many others. Also, alkoxides in which the cation isthe tetra-substituted ammonium radical such as tetramethyl ammoniummethoxide and lauryl benzyl dimethyl ammonium methoxide show activity inpromoting the radical interchange. Other substances which may be addedto further the reaction at the temperatures herein used are:alkali-metalorganic compounds containing the alkali metal atom directlybound to a carbon atom as in triphenyl methyl sodium, or to a nitrogenatom as' in potassium pyrrole; finely divided metallic potassium orsodium in xylene; and an anhydrous suspension of potassium hydroxide ina hydrocarbon solvent such as undecane.

Because of the great variety of materials that may be used" to form theactive catalyst and because the actual structure of the true catalyticmaterial is not yet accurately known, the catalytic materials have beengenerally referred to as "low temperature molecular rearrangementcatalysts. The same terminology is employed herein, although thetemperatures of reaction used may be somewhat higher than thosedisclosed in Eckey application Ser. No. 562,062.

Amounts of catalyst equivalent to one and a half per cent by weight ofsodium methoxlde based on the combined weight of the fatty acid esterand the urea have been found suitable. Smaller quantities such as 0.2per cent are effective in promoting the radical interchange, but we havefound that the reaction proceeds at a rather low rate unless 0.5 percent is employed. Larger amounts of catalyst may be used, but amountssubstantially larger than about five per cent are to be avoided in orderto avoid the emulsion diiiiculties accompanying larger usages. Thepreferred range of catalyst usage is the equivalent of about 0.5 toabout 2.5 per cent of sodium methoxide.

The catalysts that are used in practicing the present invention arehighly efficient in effecting regrouping of organic radicals, and forthis reason it is preferable to render the catalysts inactive after thedesired reaction has taken place and before conditions of reaction areallowed to change appreciably so that substantially no modificationresults during subsequent handling of the reaction mixture. At the endof the reaction, for example, it is preferable to treat the mixture withan acid reacting compound such as hydrochloric acid, phosphoric acid,carbonic acid, glacial acetic acid, etc., and thereby inactivate thecatalyst before any undesirable reversion or other change takes place.

In the use of the alkoxide and other catalysts as herein designated, theusual precautions of having the materials dry and neutral, the catalystfinely divided and well dispersed, and of excluding oxygen and carbondioxide during the reaction preferably should be observed in order toachieve optimum results.

The temperatures employed in the practice of the present invention aresuch that the acyl ureide formed during reaction will precipitate as asolid phase while at least a portion of the fatty ester and urea remainsliquid or in solution.

It is preferable to control the temperature of the reaction mix so thatthe fatty acid ester is wholly in the liquid phase, thereby establishingconditions favoring intimate contact of the fatty acid ester and theurea. However, the invention is not to be construed as excludingconditions of operation which may favor the existence of some of thefatty acid ester in solid phase. Reaction between the urea and thatportion of the ester which is in the liquid phase will take place withthe formation of fatty acid ureide even though some solid ester may bepresent in the reaction mix.

Since the solubility of acyl ureides in the fatty ester or in the ureais very low, relatively high temperatures may be employed withoutundesirable effect. However, urea decompeses readily on heating muchabove its melting point. Accordingly the reactions of the presentinvention are conducted at temperatures below 150 C. and within therange of which the lower limit is the lowest temperature at which atleast a, portion of the ester is liquid and the upper limit is thehighest temperature at which acyl ureide formed in the reaction cancrystallize from the reaction mix as it is formed. More specifically wehave found that the reaction proceeds at a desirable rate attemperatures from about 40 to 60 C. and that at temperatures within thisrange a reaction period of 15 to hours is usually sufflcient.

In the reaction of the urea with triglyceride fats, it is preferable touse more than one equivalent of combined fatty acid per equivalent ofurea. In view of the excess of triglyceride thereby added, the reactionwill result in the formation of monoand/or diglycerides depending on theexcess of fat employed. These materials, however, can be readilyseparated from the fatty acid ureide by suitable solvent washing.

Having thus described our invention, whatwe claim and desire to secureby LettersPatent is:

1. A process for the production of acyl ureides whlchcomprisescontacting a fatty acid ester of an aliphatic polyhydric alcohol withurea in the presence of an amount of a low temperature molecularrearrangement catalyst not substantially exceeding the equivalent offive per cent by weight of sodium methoxide based on the combinedweights of the said ester and the said urea, the said contact being madeat a temperature below 150 C. and below the decomposition temperature ofthe urea and within the range of which the lower limit is the lowesttemperature at which at least a portion of the said ester is liquid andthe upper limit is the highest temperature at which the fatty acidureide formed in the reaction can crystallize from the reaction mix asit is formed, and maintaining the temperature within said range whileprogressive crystallization of the fatty acid ureide takes place.

2. The process of claim 1 in which the ester is a fatty acid ester of analiphatic polyhydric alcohol having not more than 4 carbon atoms.

3. The process of claim 2 in which the temperature of reaction is fromabout C. to about C.

4. The process of claim 2 in which the mixture after reaction isextracted with a fat solvent to remove unreacted fatty ester and thenextracted with water to remove unreacted urea.

5. A process for the production of acyl ureides having from about 8 toabout 22 carbon atoms in the acyl radical, comprising contacting anester of an aliphatic polyhydric alcohol having not more than 4 carbonatoms and a fatty acid having from about 8 to about 22 carbon atoms.with urea in the presence of an amount of low temperature molecularrearrangement catalyst not substantially exceeding the equivalent offive per cent by weight of sodium methoxide based on the combinedweights of the said ester and the said urea, the said contact being madeat a temperature below C. and below the decomposition temperature of theurea and within the range of which the lower limit is the lowesttemperature at which at least a portion of the said ester is liquid andthe upper limit is the highest temperature at which the fatty acidureide formed in the reaction can crystallize from the reaction mix asit is formed, and maintaining the temperature within said range whileprogressive crystallization of the fatty acid ureide takes place.

6. A process for the production of acyl ureides comprising contacting afatty acid triglyceride with urea in the presence of a substantiallyinert triglyceride-urea mutual solvent having substantially no solventaction for the acyl ureide formed, and in the presence of anamount ofalow temperature molecular rearrangement catalyst not substantiallyexceeding the equivalent of five per cent by weight of sodium methoxidebased on the combined weights of the said triglyceride and urea, thesaid contact being made at a temperature below 150 C. and below thedecomposition temperature of the urea and within the range of which thelower limit is the lowest temperature at which at least a portion of thesaid triglyceride is liquid and the upper limit is the highesttemperature at which the fatty acid ureide formed in the reaction cancrystallize from the reaction mix as it is formed, and maintaining thetemperature within said range while pro-j gressive crystallization ofthe fatty acid ureide takes place.

7. A process for the production of a mixture of acyl ureides having fromabout 8 to about 22 carbon atoms in the acyl radical comprisingcontacting a natural triglyceride fat constituted of combined fattyacids having from about 8 to about 22 carbon atoms in the acyl radicalwith urea in the presence of a substantially inert triglyceride-ureamutual solvent having substantially no solvent action for the acylureides formed, and in the presence of an amount of a low temperaturemolecular rearrangement catalyst not substantially exceedingtheequivalent of five per cent by weight of sodium methoxide based onthe combined Weights of the said triglyceride fat and urea, the saidcontact being made at a temperature below -C. and below thedecomposition temperature of the urea and within the range of which thelower limit is the lowest temperature at which at least a portion of thesaid triglyceride fat is liquid and the upper limit is the highesttemperature at which the fatty acid ureide formed in the reaction cancrystallize from the reaction mix as it is formed, and maintaining thetemperature within said range while progressive crystallization of thefatty acid ureide takes place.

8. The process of claim 7 in which the low temperature molecularrearrangement catalyst is finely divided alkali metal alkoxide.

9. The process of claim 7 in which the low temperature molecularrearrangement catalyst is finely divided sodium methoxide.

10. The process of claim '7 in which the triglyceride fat is coconutoil.

11. The process of claim '7 in which the triglyceride fat is cottonseedoil.

12. The process of claim 7 in which the triglyceride fat is soybean oil.

EDDY W. ECKEY. ANDREW DOYLE ABBOTT.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,787,483 Lacy Jan. 6, 19312,090,594 Jacobson Aug. 17, 1937 2,358,072 Inman Sept. 12, 1944

1. A PROCESS FOR THE PRODUCTION OF ACYL UREIDES WHICH COMPRISESCONTACTING A FATTY ACID ESTER OF AN ALIPHATIC POLYHYDRIC ALCOHOL WITHUREA IN THE PRESENCE OF AN AMOUNT OF A LOW TEMPERATURE MOLECULARREARRANGEMENT CATALYST NOT SUBSTANTIALLY EXCEEDING THE EQUIVALENT OFFIVE PER CENT BY WEIGHT OF SODIUM METHOXIDE BASED ON THE COMBINEDWEIGHTS OF THE SAID ESTER AND THE SAID UREA, THE SAID CONTACT BEING MADEAT A TEMPERATURE BELOW 150* C. AND BELOW THE DECOMPOSITION TEMPERATUREOF THE UREA AND WITHIN THE RANGE OF WHICH THE LOWER LIMIT IS THE LOWESTTEMPERATURE AT WHICH AT LEAST A PORTION OF THE SAID ESTER IS LIQUID ANDTHE UPPER LIMIT IS THE HIGHEST TEMPERATURE AT WHICH THE FATTY ACIDUREIDE FORMED IN THE REACTION CAN CRYSTALIZE FROM THE REACTION MIX AS ITIS FORMED, AND MAINTAINING THE TEMPERATURE WITHIN SAID RANGE WHILEPROGRESSIVE CRYSTALLIZATION OF THE FATTY ACID UREIDE TAKES PLACE.